Juan Williams's post-speech comment seemed to reflect that same "too late" sentiment.
Williams said that Wright's hateful speech was so indelibly impressed on the minds of voters that Obama's speech wouldn't wash it away (or something to that effect).
(On a sidenote re Juan Williams: I've always respected him as the rare liberal who seems completely honest about what he believes. I really like it that he still wears an American flag lapel pin. You know he has to get lots of grief for that.)
You are right, it is too little too late and nothing will erase it because everyone knows that it is all after the fact and that anything said now, short of him publically denouncing the church, quitting the church and severing all ties to Wright, is all damage control and not sincerity. It is meant to dupe Americans into sticking with him in this campaign and nothing more. Only the blind and stupid (I guess i could have just said liberals and dims-lol) will be duped by this speech.